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  #1  
Old 09-05-2015, 03:06 PM
Padruig Padruig is offline
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Default Gabriel engine retention

I've got a Gabriel rocket (an old Centuri rocket).

Never flown it because the lack of an engine hook baffles me. The instructions just say to wrap some masking tape around the engine (A8-5, B4-6, B6-6, C6-7) before inserting. Is that really going to retain the engine and pop the chute or, as I imagine, just pop the engine and result in an unslowed rocket falling from several hundred feet?
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Old 09-05-2015, 04:14 PM
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Back in the good old days we didn't have engine hooks. Masking tape was the way to keep them in the motor tube. And sometimes it worked so well you needed pliers to get them back out!
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Old 09-05-2015, 04:18 PM
Padruig Padruig is offline
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Thanks! Good to know.

That was the other direction I could see it going, wedged so tight I wouldn't be able to extract. I guess finding the happy medium is the key.
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Old 09-05-2015, 04:44 PM
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Yes, it works... Bit of an art to it, compared to motor hooks, but not exactly rocket science LOL...

The motors tend to swell some when fired, as the casing heats up, making them tighter... So long as you can't pull the motor out with two fingers, is probly tight enough... Should be able to install it with a gentle twisting motion.... Removal is the same but usually a little tighter...

The main thing is, turn the motor casing ONLY the opposite direction from the direction you wrapped the tape around it... That way the end of the wrapped tape can't "double back" on itself by sticking to the inside of the motor tube as it's being turned...

Also, heat from the motors tend to soften the tape adhesive and make it stickier and gooier... Which can make it a lot harder to extract the motor when it cools down... Best to remove the the motor not long after flight, basically asap....

Later! OL JR
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Old 09-06-2015, 12:22 AM
PaulK PaulK is offline
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Quote:
Originally Posted by Padruig
I've got a Gabriel rocket (an old Centuri rocket).

Never flown it because the lack of an engine hook baffles me. The instructions just say to wrap some masking tape around the engine (A8-5, B4-6, B6-6, C6-7) before inserting. Is that really going to retain the engine and pop the chute or, as I imagine, just pop the engine and result in an unslowed rocket falling from several hundred feet?
This is referred to as "friction fit", and works great, once you get the hang of how tight it needs to be. I've rarely had a friction fit motor kick out.
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Old 09-06-2015, 04:57 AM
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hcmbanjo hcmbanjo is offline
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When pushing in a friction fit engine, be very careful not to grip the rocket body too tightly.
It's easy to crimp the body tube right above the top of the fins, especially on a minimum diameter BT-5 or BT-20 model.

Fred Shector gave the best advice about engine removal.
Pull a friction fit engine right after you pick it up. You can easily pull out a still warm engine.
Let it cool down and you'll have to get out the pliers.
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Old 09-06-2015, 10:00 AM
Padruig Padruig is offline
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Excellent! Thanks for the additional tips. I probably wouldn't have thought to consider the direction of the tape wrap. I'm hoping to do some launches tomorrow and I'll give the Gabriel it's long overdue first launch.
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Old 09-07-2015, 08:32 AM
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I've seen L motors friction fitted successfully!
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Old 09-12-2015, 04:29 PM
Shamous Shamous is offline
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Pliers are ok in a pinch, but a dowel works much better. Get a long oak one slightly smaller than the intenal diamater of your engine, slide it up to the nozzle and then push the rocket down. This always works. This removes the twisting motion that can ruin the rocket. And yes, it is usually easier when the engine is still warm. I have crushed to many nozzles with pliers or damaged the airframe with the twist.
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Old 09-13-2015, 12:49 PM
Padruig Padruig is offline
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Quote:
Originally Posted by Shamous
Pliers are ok in a pinch, but a dowel works much better. Get a long oak one slightly smaller than the intenal diamater of your engine, slide it up to the nozzle and then push the rocket down. This always works. This removes the twisting motion that can ruin the rocket. And yes, it is usually easier when the engine is still warm. I have crushed to many nozzles with pliers or damaged the airframe with the twist.


Good idea

Basically just need to lengthen the stick I use as an impromptu recovery wadding plunger. Thx!
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